Which statement best describes a metered-dose inhaler?

• A. A spray canister directs substance through the mouth and into the lungs.
• B. They are used only for topical skin conditions.
• C. They deliver a variable amount of medication with each actuation.
• D. They are swallowed to deliver medication.

Answer: (A)

Metered-dose inhalers deliver a measured, pressurized spray of medication through the mouth and into the lungs. With every puff, a fixed amount of drug is released, and the patient inhales to carry that dose deep into the airways. Technique matters, and spacers can help improve deposition in the lungs while reducing irritation to the mouth and throat. They are intended for inhalation, not topical skin use, and the drug is not meant to be swallowed. The defining feature is that each actuation provides a known dose, designed for delivery to the respiratory tract.